Environmental Engineering Reference
In-Depth Information
three of the major industries namely- pigments, electroplating and battery
production and their utilization are principal contributors to the release of
huge quantity of cadmium in wastewater as well as in solid waste. Thus,
there is an evident need to minimize cadmium that is being used in
various products. The inertization of cadmium not only ensures that
cadmium will be kept out of the waste stream and out of the environment,
but it also conserves valuable natural resources as well.
This chapter discusses the types of cadmium enriched waste
generated and various options to inertize cadmium containing waste
which would contribute to the sustainable and safe use of cadmium in
modern times. Chemical precipitation, solidification and land filling are
commonly used techniques for the disposal of metal containing waste all
over the world. However, this technique is rapidly declining due to its
complexity in the process including operation and maintenance,
generation of secondary pollutants and non-availability of land. Another
environment friendly approach for the inertization of metal containing
waste which is also being tested in the field is utilizing organic waste to
treat another metal contaminated waste. However, in recent times, a new
method of bio-sorption using agro waste and its derivativesis gaining
popularity owing to its various advantages, such as low cost, high
efficiency and minimization of chemicals/or biological sludge formation.
The chemical composition of agro-wastes containing, aldehydes,
carboxylic, ketones, phenolic and ether organic groups gives them an
advantage of molecular binding with heavy metals making the inert
matrices more stable. Hence, it complies with the ecological cycle of
managing Cd residues through reutilization of other wastes resulting in an
exchange mechanism to control pollution.
1.
I
NTRODUCTION
Metals and metallic compounds are important components of the human
environment and many of these compounds are essential for human health.
The mobilization of these toxic metals in our environment, however, can cause
excessive exposure which may be hazardous to human health (Nogawa et al.,
2004). One such toxic metal which is considered to cause adverse health
effects to living system is cadmium. Cadmium is an element with the symbol
Cd and atomic number 48. The soft, bluish-white metal is chemically similar
to the two other metals in group twelve of periodic table, zinc and mercury.
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